This application claims the benefit of French Application No. 98 09856 filed Jul. 31, 1998, which is incorporated herein by reference.
A mobile telephone, for a cellular network of GSM type, has the special feature of allowing its holder, if he also possesses an identification module (SIM card), to access the network through the operator which has furnished the SIM card. Thus, any holder of a SIM card can insert it into a mobile telephone and access the network. This can be done even with the mobile telephone of another person, whether borrowed, found, or stolen.
Thus, everyone knows that they must be careful with their telephone, which can be used by others.
The applicant had the idea of preventing theft of these telephone terminals at the production line, or even beyond, in the distribution channels, or back at the factory for after-sale servicing.
First of all, it will be noted that telephone terminal shall mean either the finished device, in its box, or merely the operational electronic card of the terminal.
All mobile telephones are provided with an electronic serial number, so-called international mobile equipment identity (IMEI) number, which one acquires at the parametrizing station or directly on the telephone keypad, after connecting a physical programming key for the IMEI number.
The present invention concerns, first, an antitheft procedure for mobile telephones for a cellular network, in which,
before assigning a definitive identity number to the telephone,
one assigns a provisional identity number to the telephone
one counts the cumulative duration of operation with a subscriber card SIM, as long as the definitive identity number has not been assigned,
when the cumulative duration reaches a limit time, the operation of the telephone is disabled.
Thus, the time of operation is limited, if one has not acquired the definitive identity number. And this definitive number can be acquired at the manufacturer""s packaging station or even afterwards, at the distributor, for example, at the cash register, at the time of the transaction. If the limit time is reached, it is assumed that the telephone has been stolen. Otherwise, the programming of the definitive identity number deactivates the antitheft protection.
It will be noted that in a preferred embodiment, the antitheft protection is not finally activated until one uses the telephone with a subscriber card SIM, i.e., a priori, for a telephone call on the network. Thus, the stages of mere manufacture, adjustment, testing or debugging, which are done with a test SIM card or without a SIM card, are not affected by the protection of the invention.
It will be further noted that the procedure of the invention does not in any tangible way disturb the tools, methods, or practices used on the production line.
Advantageously, one will count down, from the limit time, the tests on the actual network with normal SIM card.
Preferably, the operation of the telephone with a test SIM card will be disabled after the time limit of operation without assignment of the definitive identification number.
Preferably, again, each time the device goes idle, the cumulative duration is memorized and saved in EEPROM.
This can be memorized in a region not accessible to the usual maintenance means.
The invention also concerns a mobile telephone for a cellular network, outfitted with antitheft protection means comprising:
means of time counting, which control
means of threshold comparison, which command
means of disabling the operation of the telephone, which command a keypad (3) of the telephone,
means (21) commanded by programming of an identity number IMEI in order to short-circuit the time counting means.